Controlling device for electric motors.



G. H. DORGELOH.

GONTROLLING DEVICE FOR ELECTRIC MOTORS.

APPLIOATION FILED JAN. 6, 1910.

Patented Mar. 5, 1912.

-Q U Witnesses:

Inventor STATES PATENT orr oa.

GEORGE H.

DORGELOH, OF SOHENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A. CORPORATION OF NEW YORK.

CONTROLLING DEVICE FOR ELECTRIC MOTORS.

Specification of Letters Patent.

Patented Mar. 5, 1912.

To all whom it may concern.

Be it known that I, GEORGE H. DoRoELon, a citizen of the United States, residing at Schenectady, county of Schenectady, State of New York, have invented certain new and useful Improvements in Controlling Devices for Electric Motors, of which the following is a specification.

This invention relates to the control of electric motors and has for its object the provision of meanswhereby an electric motor may be controlled throughout a wide range of speed in a reliable and efiicient manner.

My invention relates more specifically to the control of electric motors operating upon a multi-voltage system, one of the objects being to change the motor from one voltage to another in a reliable manner and thereby obtain a greater range of motor speed.

Other objects of my invention will appear in the course of the following specification, in which I have shown my invention embodied in concrete form for purposes of illustration.

In the accompanying drawings illustrating my invention, Figure 1 is a diagram-' matic view of my device showing the circuit connections; and Fig. 2 is aside elevation of the controller.

Referring to the drawing, a b and 0 represent the three conductors of a multivoltage system which may be what is known as the three wire system. A represents the armature and F the shunt field of an electric motor to be operated upon this system. The controller proper consists of a controlling arm 1 pivoted at 2, having an operating handle 3, and arranged to control a series of contactors which operate to cut out the resistance 4. The coils of the contactors 5, 6, 7 and 8 are connected with the studs. 9 adapted to be engaged by contact 10 on the arm 1. The arrangement is such that as the arm 1 passes over the studs .9 in a clock; wise direction the contactors 8, 7, 6, and 5 will be operated successively to cut out sections of resistance 4. The last of the studs 9 is connected with a conducting segment 11 through a resistance 12. The segment 11 terminates at the point at which the controlling arm reaches the maximum speed on the low voltage and is there joined to an insulating segment 13-. After the arm leaves this segment, it passes on to a series of studs terminals for the resistance 18.

14 cross connected with the studs 9 so as to again operate the contactors 8, 7, 6, and 5. These studs are followed by another conducting segment 15 for maintaining the armature circuit, while the field strength is varied. The contact 10 on arm 1 likewise engages a series of segments and contact studs arranged concentric-with the studs just described, for varying the field strength. These consist of a conducting segment 16 for maintaining the field strength while the resistance in the armature circuit is being cut out and .a series of studs 17 forming sistance is arranged to be connected in the field circuit for gradually increasing the speed of the motor after the resistance in the armature circuit is eliminated. The studs 19 are engaged by the contact 10 after it leaves the last contact 17 for the purpose of cutting out the field resistance to build up the field of the armature circuit is opened on the low voltage and before the armaturecircuit is closed on the higher voltage. The segment 20 is provided for maintaining the field circuit constant while the armature resistance is being cut out on the higher voltage and the studs 21 are cross connected with the studs 17 for inserting the resistance 18 in the field circuit on the higher volta e. A resistance 22 is likewise provided or further increasing the speed if desired. Outside of the.two series of contacts and studs just described and concentric therewith, is a segment 23 arranged to be enga ed by the contact 10 substantially throng out its entire range of movement. This segment is joined to a stud 24 at the starting position of the arm by the resistance 25. The extreme end of the contact 10 engages a stud 26 connected with the segment 27 by a resistance 28. segment extends travel of the controlling arm and is followed by another segment 28 of substantially the same length. Between the two segments 27 and 28- are two studs 29 and 30, separated This re- This" throughout about half the by an insulating section 31, a resistance 32.

ice

connected with the stud 29 is arranged to connect the motor armature on the high voltage, that is, between the mains a and a. An electromagnetic switch 35, having one terminal connected with the stud 24, is provided with two contacts 36 and 37. Contact 36 closes the armature circuit through the resistance 4 and the contact. 37 closes a circuit through the coils of the contactors 5, 6, 7 and 8. A push-button switch 38 is arranged to open the circuit of the coil of switch when it is desired to stop the motor. A relay 39 having its terminals connected across the armature A is arranged to operate two contacts and 41, for purposes hereinafter described.

The arrangement of circuits and mode of operation of my device are as follows: To start the motor, the arm 1 is moved so that contact 10 engages studs 24 and 26, and likewise engages the first of studs 9. This will result in closing a circuit through the electromagnetic switch 33 from line a to stud 26, arm 1, and back to line 0 through conductor 42. This will also energize electromagnetic switch 35 from the line a to stud 24, arm 1,

and back to line through conductor 42. The

switch 35 will immediately close, thereby completing a circuit through the coil of contactor 8 from the line a through contact 37, stud 9 and back to line through conductor 42. The switch 33 is likewise closed and the armaturecircuit is now completed from line a across contact 36, armature A, contactor 8', resistance 4 and back to line b.- The armature is now connected across the low voltage with the resistance 4 in series therewith.

' As the arm 1 is moved in a clockwise direction and engages the studs 9 successively, the contactors 7, 6, 5-close, one after another, and thereby cut out sections of resistance 4 until finally the armature is connected directly across the low voltage. While the armature resistance is being cut out, the field is maintainedat full strength through the segment 16. When the arm passes ofi of the studs 9, the studs 17 are engaged and the sections of resistance 18 are gradually cut into the field circuit so as to increase the speed. While this is being done, the armature circuit is maintained through t-he'segment 11. When all of the resistance 18 is cut into the field circuit, the arm 1, by passing ofi' of the segment 27, opens switch 33, thereby opening the armature circuit. As the movement of the arm is continued in a clockwise direction, the studs 19 are engaged,-which gradually cuts out the field resistance and builds up the field strength before the armature circuit is closed across the higher voltage. While this is being done, the armature circuit is open, since the contact 10 is in engagement with the insulation section 31. As soon as the arm 1 passes onto the stud 29 the switch 34 is closed to complete a circuit through the armature across to proper speed. This is so since the coil of the relay 39 is connected across the armature terminals and operates the contact 41 in the circuit of coil 34. If, therefore, the motor is up to proper speed When the arm reaches the stud 29, the counter E. M. F. of the motor will be sufiicient to energize the relay 39 and close a circuit through the relay 34 as follows: from line a to coil of switch 34, contact 41, conductor 44, to stud 29, thence to arm 1 and back to the main 0. At the same time that it engages stud 29, the arm engages the studs 14 which again successively energizes the contactors 8, 7, 6, 5 to gradually cut the resistance 4 out of the armature circuit. This time the armature circuit is as follows: from main at, through contact 36, armature A, resistance 4, conductor 43, switch 34, to line 0. Starting resistance is now gradually cut out and the strength of the field is then varied by engagement with the studs 21 so as tpibrlng the motor up to its highest speed. Ifl, while the motor is running on the low voltage inany position ,of the controlling arm, the voltage should fail, theswitches 33 and 35 will open the motor circuit. In order to again start the motor, the arm 19 must be brought back into engagement with the studs 24 and 26, since the resistances 25 and 28 are suflicient to prevent these switches from closing, but

not sufiicient to preirent: their being held closed. Likewise, if voltage should fail while the motor is running on the high voltage, switches 34 and 35 will open and the controlling arm must again be brought back to the starting position of the low voltage before the armature circuit can be closed. As the arm is moved back from the high volt-age to the low voltage it engages the stud 30 to close the switch 33. This switch will not, however, close unless the armature A is running at proper speed, since again the relay 39 must be closed, as the circuit of the switch 33 must pass through the contact 40 as follows: from the line a, coil 33, conductor 46, contact 40, conductor 47, contact 30, and back to line through conductor 42. This relay 39 therefore prevents injurious efiects in case the operator should stop on the segment 31 between the opening of the low voltage and the closing of the high voltage, or vice versa, since the motor must always be running at proper speed before the armature circuit can be closed. If at any time it is desired to stop the motor quickly, the push button 38 may be operated to denergize the coil of switch 35, thereby opening the motor circuit. In order to start it again, the controlling arm must be brought to the starting position on the low voltage.

the motor from danger due to starting on a weakened field, or without any resistance in series with the armature. The gradual strengthening of the field between the open-' ing of the circuit on one volta e and closing it on the next, which may called the coasting feature, I regard as im ortant. I likewise regard the relay for insurlng that the motor is up to proper speed before it is connected to l1ne as a very important feature. It should, moreover, be understood that while I have described my invention as embodied in concrete form and as operating in a specificmanner for purposes of illustration, I do not limit my invention thereto, since various modifications thereof will suggest themselves 'to those skilled in the art without departing from the spirit of'my invention, the scope of which is set forth in the annexed claims. I

What I claim as new and desire to secure by Letters Patent of the United States, is 1. A device for controlling electric motors on a multi voltage system comprising a rheostat arranged to start the motor on low and high voltage respectively, and means controlled by conditions in the motor circuit for preventlng the starting on the higher voltage, v

2. A device for controlling electric motors on a multivoltage system comprising a rheostat arranged to start the motor on low and high voltage; respectively, and means controlled by'the speed of the motor for preventing the starting under higher voltage.

3. A device for controlling electric mo- 7 tors on a multi voltage system comprisin a resistance, a controlling member there or, electromagnetic switches controlled by; said member for closing the motor circuit through the resistance on the high and low voltage respectively, and means .for preventingthe operation on the high voltage switch until the motor reaches a predetermined speed.

4, A device for controlling electric m0- tors on a multi voltage system comprisin a starting resistance, a controlling mem er therefor arranged to start the motor through the resistance on one voltage and then increase the speed on the other voltage, and means controlled by the speed of the motor for preventing the closing of the motor circuit on the higher voltage.

5. A'device for controlling electric motors on a multi-voltage system comprising a rheostat arranged to successively start the motor, weaken the field,- and open the armature circuit on the low' voltage, and then successively strengthen the field and start the motor on the high voltage, and means for preventing the closing of the motor circuit under-certain conditions.

6. A device for controlling electric motors on a multi-voltage system comprising a rheostat arranged to successively start the motor, weaken the field and open the armature circuit on low voltage and'then succes-' sivelytstrengthen the field, close the armature circuit andincrease the speed of the motor on the high voltage, and means for preventing the closing of the circuit on the high voltage until the motor reaches a predetermined speed.

7. A device for controlling electric motors on a multi-voltage system comprising a rheostat arranged to successively start the motor, weaken the field and open the armature circuit on low voltage, and then successively strengthen the field, close thearmature circuit, and increase the speed of the motor on the high voltage, means for preventing the. closing of the circuit on the high voltage until the motor reaches a predetermined speed and an electro-magnetic switch closable only in the starting position of the low-voltage for closing the motor circuit on both voltages.

8. tA'device for controllingelectric motors on a multi-voltage system comprisin a resistance, a controlling member there or,

ond switch until the motor reaches a predetermined speed.

In witness whereof, I have hereunto set my hand this 5th da of January, 1910. GEOR E DORGELOH.

Witnesses I I BENJAMIN B. HULL,

HELEN ORronD. 

